Distinguish between missing file and read error

rstudio · Nov 30, 2018 · f3e487d · f3e487d
1 parent 3cbe074
commit f3e487d
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Showing 3 changed files with 36 additions and 15 deletions.
diff --git a/src/filedatasource-unix.cpp b/src/filedatasource-unix.cpp
@@ -6,26 +6,31 @@
 #include <unistd.h>
 #include <errno.h>
 
-int FileDataSource::initialize(const std::string& path, bool owned) {
+FileDataSourceResult FileDataSource::initialize(const std::string& path, bool owned) {
   // This can be called from either the main thread or background thread.
 
   _fd = open(path.c_str(), O_RDONLY);
   if (_fd == -1) {
-    _lastErrorMessage = "Error opening file " + path + ": " + toString(errno) + "\n";
-    return 1;
+    if (errno == ENOENT) {
+      _lastErrorMessage = "File does not exist: " + path + "\n";
+      return FDS_NOT_EXIST;
+    } else {
+      _lastErrorMessage = "Error opening file " + path + ": " + toString(errno) + "\n";
+      return FDS_ERROR;
+    }
   }
   else {
     struct stat info = {0};
     if (fstat(_fd, &info)) {
       _lastErrorMessage = "Error opening path " + path + ": " + toString(errno) + "\n";
       ::close(_fd);
-      return 1;
+      return FDS_ERROR;
     }
 
     if (S_ISDIR(info.st_mode)) {
       _lastErrorMessage = "File data source is a directory: " + path + "\n";
       ::close(_fd);
-      return 1;
+      return FDS_ISDIR;
     }
 
     _length = info.st_size;
@@ -37,7 +42,7 @@ int FileDataSource::initialize(const std::string& path, bool owned) {
       // It's OK to continue
     }
 
-    return 0;
+    return FDS_OK;
   }
 }
 

diff --git a/src/filedatasource.h b/src/filedatasource.h
@@ -3,6 +3,16 @@
 
 #include "uvutil.h"
 
+
+// Status codes for FileDataSource::initialize().
+enum FileDataSourceResult {
+  FDS_OK = 0,     // Initialization worked
+  FDS_NOT_EXIST,    // File did not exist
+  FDS_ISDIR,      // File is a directory
+  FDS_ERROR       // Other error
+};
+
+
 class FileDataSource : public DataSource {
 #ifdef _WIN32
   HANDLE _hFile;
@@ -16,7 +26,7 @@ class FileDataSource : public DataSource {
 public:
   FileDataSource() {}
 
-  int initialize(const std::string& path, bool owned);
+  FileDataSourceResult initialize(const std::string& path, bool owned);
   uint64_t size() const;
   uv_buf_t getData(size_t bytesDesired);
   void freeData(uv_buf_t buffer);

diff --git a/src/webapplication.cpp b/src/webapplication.cpp
@@ -189,9 +189,11 @@ boost::shared_ptr<HttpResponse> listToResponse(
   // - body: Character vector (which is charToRaw-ed) or raw vector, or NULL
   if (std::find(names.begin(), names.end(), "bodyFile") != names.end()) {
     FileDataSource* pFDS = new FileDataSource();
-    int ret = pFDS->initialize(Rcpp::as<std::string>(response["bodyFile"]),
-                               Rcpp::as<bool>(response["bodyFileOwned"]));
-    if (ret != 0) {
+    FileDataSourceResult ret = pFDS->initialize(
+      Rcpp::as<std::string>(response["bodyFile"]),
+      Rcpp::as<bool>(response["bodyFileOwned"])
+    );
+    if (ret != FDS_OK) {
       REprintf(pFDS->lastErrorMessage().c_str());
     }
     pDataSource = pFDS;
@@ -508,16 +510,20 @@ boost::shared_ptr<HttpResponse> RWebApplication::staticFileResponse(
 
   // Self-frees when response is written
   FileDataSource* pDataSource = new FileDataSource();
-  int ret = pDataSource->initialize(local_path, false);
+  FileDataSourceResult ret = pDataSource->initialize(local_path, false);
 
-  if (ret != 0) {
+  if (ret != FDS_OK) {
     // Couldn't read the file
     delete pDataSource;
 
-    if (sp.options.fallthrough.get()) {
-      return nullptr;
+    if (ret == FDS_NOT_EXIST || ret == FDS_ISDIR) {
+      if (sp.options.fallthrough.get()) {
+        return nullptr;
+      } else {
+        return error_response(pRequest, 404);
+      }
     } else {
-      return error_response(pRequest, 404);
+      return error_response(pRequest, 500);
     }
   }